How to Adjust Hot Water Heater Temperature

Be safe—keep the dial at 120 degrees F

Learn a surefire method for finding the right setting on the hot water heater dial—cool enough to avoid accidental burns, but hot enough for a long, relaxing bath or shower.

By the DIY experts of The Family Handyman Magazine
:April 2005

TIME

Instant!

COMPLEXITY

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COST

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Step-by-Step

A slight turn of the dial makes water heaters safer

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Fine-tune the water heater temperature

To find the recommended temperature of 120 degrees F. on an unnumbered dial, check the temperature of the water at different settings. Make a mark on the dial once you find the setting.

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Check the temperature

Run the hot water for several minutes, then check the temperature in a glass or pot with a thermometer.

Plain old tapwater can be dangerous. Water heaters set too high send thousands (mostly children) to hospitals each year with burns. Most safety experts recommend a setting of 120 degrees F. But finding that setting on the dial isn't easy—most dials aren't labeled with numbers. If the stickers on the water heater don't tell you how to set the temperature and you can't find the owner's manual, use this method: Run hot water at the tap closest to the water heater for at least three minutes. Then fill a glass and check the temperature. If the water is above 120 degrees, adjust the dial, wait about three hours and check again. Repeat until you get 120-degree water. For a final test, check the temperature the following morning, before anyone uses hot water.